1600---2000?

Well so id have to work on my endgame--coz tctics im quite good at it,i can defend quite well,attack quite goood.

Lots of good advice here. As a 2000+ OTB I win most endgames against lower or even equally rated players, as endgames come very naturally to me. I work on tactics a lot since that's my weak point. Understand the openings you play, not so much to get an advantage but to get to a position where you know how to proceed. Know what you're weak at and work on that.

Well Opening is very good-i do no know much theory but the ideas

Most of comments above are right. There isn't one thing but a lot of them. But let me generalised: strategy and positional play particularly. Most of newbies are discussing about openings everyday but most of them (not all) have no idea of strategy. Just pick a book about strategy (like John Watson's or Dvoretsky's) and study it properly. You will see how your level of play will raise strongly. Two friends of mine had1200 rating here in lichess and after read those 2 books they reached 1700 very quickly.

well ok but im 1600-1700!!!!